Put simply, a Local Area Network (LAN) is a group of computers and other devices that are connected together over a network and are all in the same location—typically within a single building like an office or home. But, let’s take a closer look.
What is a LAN?
So we know two things about a LAN just from from the name “Local Area Network”—the devices on them are networked and they’re local. And it’s that local part that really defines a LAN and distinguishes it from other types of networks like Wide Area Networks (WANs) and Metropolitan Area Networks (MANs).
LANs are typically confined within a small area—usually one building, but that’s not a firm requirement. That area might be your home or small business, and it could contain just a few devices. It might also be a much larger area, like an entire office building that contains hundreds or thousands of devices.
But regardless of size, the single defining characteristic of a LAN is that it connects devices that are in a single, limited area.
The advantages of using a LAN are the same advantages as having any devices networked together. Those devices can share a single internet connection, share files with one another, print to shared printers, and so on.
On bigger LANs, you’ll also find dedicated servers that host services like global user directories, email, and access to other shared company resources.
What Kinds of Technology Are Used in a LAN?
The types of technology used in a LAN is really dependent on the number of devices and the services provided on the network. The two basic connection types used on modern LANs—no matter the size—are Ethernet cables and Wi-Fi.
On a typical home or small office LAN, you might find a modem that provides an internet connection (and a basic firewall against intrusion from the internet), a router that lets other devices share that connection and connect to one another, and a Wi-Fi access point that lets devices access the network wirelessly. Sometimes, those functions are combined into a single device. For example, many ISPs provide a combination unit that serves as a modem, router, and wireless access point. Sometimes, you might also find devices called switches that let you split up a single Ethernet connection into multiple connection points.
On bigger LANs, you’ll typically find the same kinds of networking gear, just on a much bigger scale—both in terms of how many devices are used and how powerful they are. Professional routers and switches, for example, might service many more simultaneous connections than their home counterpoints do, provide more robust security and monitoring options, and allow a good bit more customization. Professional level Wi-Fi access points often allow management of many devices from a single interface, and provide better access control.
So, What Are WANs and MANs?
Wide Area Networks (WANs) and Metropolitan Area Networks (MANs) are actually pretty similar. You’ll even see the term Campus Area Networks (CANs) popping up occasionally. They are all somewhat overlapping terms, and nobody really agrees on a firm distinction. Essentially, they are networks that connect together multiple LANs.
For people who do make the distinction, a MAN is a network made up of multiple LANs that are connected together via high speed networks and are all contained within the same city or metropolitan area. A WAN is also made up of multiple LANs, but spans an area greater than a single city and may be connected by different types of technologies, including the internet. And a CAN, of course, is a network made up of multiple LANs that spans a school campus.
Really, though, if you want to just think of all of them as WANs, it’s okay with us.
For a classic example of a WAN, think of a company that has branches in three different locations across the country (or the world). Each location has its own LAN. Those LANs are connected together as part of the same overall network. Maybe they’re connected via dedicated, private connections, or maybe they’re connected together over the internet. The point is that the connection between the LANs is not considered as speedy, reliable, or secure as the connections between devices on the same LAN.
In fact, the internet itself is just the worlds biggest WAN, connecting together many thousands of LANs across the world.